busy signal

• 忙碌信号,忙音信号,忙音,占线信号

busy signal的用法和样例：

例句

1. I dialed her number, but it was busy.
   我拨了她的号码但却是忙音。
2. In communications,a condition that occurs in a network when no circuits are available and a busy tone is returned to the calling part.
   在通信技术中，当无线路可用因而有忙音返回给主呼叫用户时网络的一种状态。